The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception

Question

I'm working with EF5 in a MVC 4 aspnet website. Locally, everything works just fine, but when I publish it to the IIS and try to enter, I get the error

"The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception."

Detailed exception

An error occurred creating the configuration section handler for entityFramework: Configuration for DbContext type 'GdpSoftware.Server.Data.GdpSoftwareDbContext, GdpSoftware.Server.Data' is specified multiple times in the application configuration. Each context can only be configured once. (E:\App\web.config line 104)

I checked previous question in StackOverflow, and I already uninstalled and reinstalled through Nuget EntityFramework and checked that each reference to it in each project is EF5. I also checked that the selected framework in each project is 4.5.

Any idea, What might be causing the issue? Thanks! Guillermo.

web.config

<?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
  <configSections>
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />

  <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 --></configSections>
  <connectionStrings>
    <add name="GdpSoftwareConnectionString" connectionString="Persist Security Info=False;User ID=user;Password=password;Initial Catalog=databasename;Data Source=server" providerName="System.Data.SqlClient" />
    <add name="GdpSoftware.Server.Data.GdpSoftwareDbContext" connectionString="GdpSoftware.Server.Data.GdpSoftwareDbContext_ConnectionString" providerName="System.Data.SqlClient"/>
    <add name="GdpSoftware.Server.Ui.Web.Models.UsersContext" connectionString="GdpSoftware.Server.Ui.Web.Models.UsersContext_ConnectionString" providerName="System.Data.SqlClient"/>
  </connectionStrings>
  <appSettings>
    <add key="webpages:Version" value="2.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="PreserveLoginUrl" value="true" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5" />
    <authentication mode="Forms">
      <forms loginUrl="~/Account/Login" timeout="2880" />
    </authentication>
    <pages>
      <namespaces>
        <add namespace="System.Web.Helpers" />
        <add namespace="System.Web.Mvc" />
        <add namespace="System.Web.Mvc.Ajax" />
        <add namespace="System.Web.Mvc.Html" />
        <add namespace="System.Web.Optimization" />
        <add namespace="System.Web.Routing" />
        <add namespace="System.Web.WebPages" />
      </namespaces>
    </pages>
    <!-- BEGIN - TO SEE THE ERRORS ON THE DEPLOYMENT-->
    <customErrors mode="Off" />
    <!-- END - TO SEE THE ERRORS ON THE DEPLOYMENT-->
  </system.web>
  <system.webServer>
    <!-- BEGIN - TO SEE THE ERRORS ON THE DEPLOYMENT-->
    <httpErrors errorMode="Detailed" />
    <asp scriptErrorSentToBrowser="true" />
    <!-- END - TO SEE THE ERRORS ON THE DEPLOYMENT-->
    <validation validateIntegratedModeConfiguration="false" />
    <handlers>
      <remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" />
      <remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" />
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
      <add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
    </handlers>
    <staticContent>
      <mimeMap fileExtension=".mustache" mimeType="text/plain" />
    </staticContent>
    <security>
      <requestFiltering>
        <fileExtensions>
          <add fileExtension=".mustache" allowed="true" />
        </fileExtensions>
      </requestFiltering>
    </security>
  </system.webServer>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Castle.Windsor" publicKeyToken="407dd0808d44fbdc" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-3.2.0.0" newVersion="3.2.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.5.0.0" newVersion="4.5.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin.Host.SystemWeb" publicKeyToken="31bf3856ad364e35" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-1.0.0.0" newVersion="1.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Castle.Core" publicKeyToken="407dd0808d44fbdc" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-3.2.0.0" newVersion="3.2.0.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
    <contexts>
      <context type="GdpSoftware.Server.Data.GdpSoftwareDbContext, GdpSoftware.Server.Data" disableDatabaseInitialization="true">
        <databaseInitializer type="System.Data.Entity.MigrateDatabaseToLatestVersion`2[[GdpSoftware.Server.Data.GdpSoftwareDbContext, GdpSoftware.Server.Data], [GdpSoftware.Server.Data.Migrations.Configuration, GdpSoftware.Server.Data]], EntityFramework" />
      </context>
    </contexts>
  </entityFramework>
</configuration>

Answer 1

Do the following in the App.config file,

1. Put the connectionStrings element is after the configSections element.
2. Put the startup element after the connectionStrings element.

<?xml version="1.0" encoding="utf-8"?>
 <configuration>
   <configSections>
         <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=4.3.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
   </configSections>
   <connectionStrings>
         <add name="SchedulingContext" connectionString="Data Source=XXX\SQL2008R2DEV;Initial Catalog=YYY;Persist Security Info=True;User ID=sa;Password=XXX"   providerName="System.Data.SqlClient"/>
   </connectionStrings>
   <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>       
 </configuration>